Quote from: thecryptokeeper on June 08, 2013, 04:58:08 PM

I figured out it was the rail from testing each GPU with it's closest rail. Then I found the GPU that didn't function in cgminer. So I tried it with a different rail and it started working. Hence I moved the power cable to another rail and got all five working. I could probably do six again by swapping out PSUs but the power consumption was going past the 1600W rating when I had six going. I had to underclock and turn intensity down to get it stable. If I were to do six again, I would use two 1000W PSUs.

To get six GPUs working, I used 13.1 on Windows 8 a 12.6 trick. I can't find the link at the moment but it's somewhere on this forum about six GPUs to work on a motherboard. Also no shorting PCIe slots on the MSI Z77 GD65.

Quote from: gregyoung14 on June 08, 2013, 07:45:03 AM

I have the same PSU and Graphics cards as you and am struggling to get all six working. How did you figure out that one of your rails was malfunctioning? Also, did windows 8 see all six right off the bat? Just installed 13.1 and they worked?

I'm using an A4 FM2 processor with a gigabyte F2A85x-UP4 but so far its been nothing but a pain in the ass lol. If you have 6 msi r7950 twin frozr working good in windows 8 with that msi board, I might be making a return to amazon soon lol

When you tested each GPU, did you test them individually or with the others plugged in. Or one by one. I'll give that a try both ways in just a moment. So should I just count on only using x5 with a 1600w? If so thats fine for now.

Any ideas how I could find the 12.6 trick for windows 8? I had windows 8 with 13.1 earlier and device manger saw all 5 of them that were plugged in at the time just fine. However, when cgminer started I would see all the hash rates jump up where there suppose to be, but then the screen would either freeze or go blank and I would loose all control, it was like the driver was crashing.

Not having to short any pcie slots would be nice, I had to short one of the 1x on my gigabyte board. It has no problem though seeing all 6 in ubuntu or xubuntu, I just cant run cgminer with a thread concurrency above 1792 or all the cards but one report as off, on the flip side if i run at 1792 they all hash at 150 or so, but i get 10 HW error a second a card so thats issue as well.

I'd prefer to stick with windows 7/8 so that I can utilze afterburner to turn down the voltage, though I suppose a bios flash is always an option?